Site-directed mutagenesis of a potyvirus coat protein and its assembly in Escherichia coli

Multiple copies of the Johnsongrass mosaic virus coat protein synthesized in Escherichia coli can readily assemble to form potyvirus-like particles. This E. coli expression system has been used to identify some of the key amino acid residues, within the core region of the coat protein, required for assembly. The two charged residues R194 and D238 previously proposed theoretically to be involved as a pair in the construction of a salt bridge crucial for the assembly process were targeted for site-directed mutagenesis. The results from our experiments suggest that the two residues are required for the assembly process but are not necessarily involved as a pair in a common salt bridge.

Mechanisms and dynamics of mechanical strengthening in ligament-equivalent fibroblast-populated collagen matrices

We have measured the dynamics of extracellular matrix consolidation and strengthening by human dermal fibroblasts in hydrated collagen gels. Constraining matrix consolidation between two porous polyethylene posts held rigidly apart set up the mechanical stress which led to the formation of uniaxially oriented fibroblast-populated collagen matrices with a histology resembling a ligament. We measured the mechanical stiffness and tensile strength of these ligament equivalents (LEs) as a function of age at biweekly intervals up to 12 weeks in culture using a mechanical spectrometer customized for performing experiments under physiologic conditions. The LE load-strain curve changed as a function of LE age, increasing in stiffness and exhibiting less plastic-like behavior. At 12 weeks, LEs had acquired up to 30 times the breaking strength of 1-week-old LEs. Matrix strengthening occurred primarily through the formation of BAPN-sensitive, lysyl oxidase catalyzed crosslinks. Sulfated glycosaminoglycan (GAG) content increased monotonically with LE age, reaching levels that are characteristic of ligaments. Cells in the LEs actively incorporated [3H]proline and [35S]sulfate into the extracellular matrix. Over the first three weeks, DNA content increased rapidly but thereafter remained constant. This data represent the first documentation of strengthening kinetics for cell-assembled biopolymer gels and the results suggest that this LE tissue may be a valuable model for studying the cellular processes responsible for tissue growth, repair, and remodeling.

The change of C-fos expression in ovariectomized rats following electroacupuncture treatment--an immunohistochemistry study

The roles of electroacupuncture (EA) in regulating the function of ovulation in rat have been investigated; however, the systematic study for the involvement of neural population of central nervous system (CNS) in acupuncturing the ovariectomized rat for promoting functional recovery has not been well understood. The present research was designed to examine, by C-fos immunocytochemistry, the distribution of Fos labelled neuron in CNS after acupuncturing the point of "Zhong-Ji (RN3)", "Guan-Yuan (RN4)", "San-Ying-Jiao (SP6)" and "Zi-Gong (EXCA1)" in ovariectomized rat. The area occupied by Fos protein labelled neuron, two hours after ovariotomy, was detected in medial preoptic nucleus (MPN), lateral preoptic nucleus (LPN), suprachiasmatic nucleus (SCN), paraventricular nucleus of the hypothalamus (PANH), medial amygdala nucleus (MAN), periventricular nucleus of the hypothalamus (PVNH), ventromedial nucleus of the hypothalamus (VNH), and arcuate nucleus (AR). The C-fos immunoreactive labelled neurons disappeared two weeks later following ovariotomy. The rat, recovering for two weeks after ovariotomy, received EA, and many specific Fos labelled cell were observed in LPN, PVNH, VNH, SCN and especially in AR, PANH and MPN, but not any labelled neuron could be found in MAN. No obvious C-fos expression was shown in these areas in the control group and EA group without ovariotomy. These results indicate that the above structures involved in regulating the function of hypothalamus-pituitary-ovarian axis and EA could modulate this function through effects on the above nuclei.

Laparoscopic trocar-assisted colpotomy

Trocar-assisted transvaginal colpotomy was performed in 17 patients to remove large pathologic specimens during laparoscopic operations when the specimen could not be extirpated through the laparoscopic ports. Under direct laparoscopic visualization, colpotomy was performed using a 10- or 11-mm disposable trocar without the sleeve. The trocar was removed, a ring forceps was placed through the incision, the incision was enlarged, and the mass was grasped with the ring forceps and removed. This technique is safe, fast, and easy to perform. In addition, smoke is not created and potential electrocautery damage to pelvic structures is avoided.

Suppression by dietary alcohol of resistance to Cryptosporidium during murine acquired immune deficiency syndrome

Significant immunological changes occur following LP-BM5 murine leukemia retrovirus infection as well as chronic alcohol consumption. Retrovirus infection which has proceeded to murine AIDS permitted persistent Cryptosporidium infection, while non-retrovirus infected mice were resistant. Dietary alcohol provided until the day before parasite challenge did not affect resistance in controls, but increased the numbers of oocysts in the feces of retrovirus suppressed mice. Mortality was significant in retrovirus infected mice, and exacerbated slightly by dietary ethanol, while all controls survived parasite challenge. The retrovirus infected mice had greatly reduced numbers of intestinal CD4+ T helper cells and IgA+ B cells, which may explain their loss of intestinal resistance. Clearly, the severely immunosuppressed animals with murine AIDS were more sensitive to alcohol consumption than uninfected controls. This suggests that alcohol can synergize with murine retrovirus infection to exacerbate loss of resistance to an opportunistic pathogen common in human AIDS patients.

Hepatitis B virus DNA integration and expression of an erb B-like gene in human hepatocellular carcinoma

Southern blot studies on Hepatitis B Virus (HBV) DNA integration in 13 human hepatocellular carcinomas (HCCs) patients revealed the presence of several distinct HBV integration sites in different human liver disease patients. In one HCC patient the DNA fragment containing the HBV integration also hybridized to an erb B probe. The erb B/HBV co-migrating DNA fragment was cloned and sequenced, and showed that HBV DNA is integrated next to a cellular DNA fragment which is homologous to the tyrosine protein kinase domain of the human epidermal growth factor receptor gene and other cell surface receptor genes. The virus-integrated cellular DNA sequence is expressed in this HCC patient, suggesting a possible role for this gene in hepatocarcinogenesis.

[Anti-inflammatory and analgesic actions of artificial and fermentative Ganoderma sinense (AFGS)]

Both AFGS and natural Ganoderma sinense (NGS) have obvious anti-inflammatory and analgesic effects for arthritis in rats induced by carrageenan and the pain reaction in mice induced by hot scalding as well as HAC-induced writhing. AFGS also can reduce the edematous swelling of mice's ears, reduce the capillary permeability of mice skin and obviously inhibit cotton pellets granuloma implanted in rats. It can promote cytophagy capacity of the reticular endothelial cells in mice. No irritation on the gastric mucosa in rats has been observed.

Immunosuppression induced by nitric oxide and its inhibition by interleukin-4

Mice immunized with attenuated Salmonella typhimurium, strain SL3235, while protected against virulent challenge, are unable to mount in vivo and in vitro antibody responses to non-Salmonella antigens, such as tetanus toxoid and sheep red blood cells, and exhibit profoundly suppressed responses to B and T cell mitogens. Suppression of antibody responses is mediated by macrophage (M phi)-released soluble factors, and is completely reversed by treatment with interleukin (IL)-4. The present report identifies the suppressor factor as nitric oxide (NO), and provides evidence for a mechanism by which IL-4 abrogates suppression. Suppressed antibody responses correlated with high levels of NO secretion by splenocytes of SL3235-immunized mice. NO production was observed only in cultures consisting of the adherent cell fraction of immune splenocytes. Further, immunosuppression was reversed by NG-monomethyl-L-arginine (NMLA), a competitive inhibitor of NO synthesis, and was completely blocked by the addition of excess L-arginine. Treatment with IL-4, or anti-interferon (IFN)-gamma monoclonal antibody (mAb), also abrogated suppression. Optimal reversal of suppression was observed only when NMLA, IL-4, or anti-IFN-gamma mAb, was added at day 0 of the 5-day plaque-forming cell assay. Treatment with either IL-4 or anti-IFN-gamma mAb also lead to a sharp inhibition of NO production by immune spleen cells. Moreover, the addition of IL-4 to splenic adherent M phi inhibited their ability to generate NO. Our data characterize an immunoregulatory pathway, involving IFN-gamma and NO, by which M phi mediate immunosuppression and identify IL-4 as a potent inhibitor of this pathway.

Incompletely resected advanced squamous cell carcinoma of the head and neck: the effectiveness of adjuvant vs. salvage radiotherapy

Between 1982 and 1988, 441 patients were treated at the Medical College of Virginia for AJC Stage III and IV squamous cell carcinoma of the head and neck. We report here on 84 patients whose tumors were incompletely resected based on histopathological margins of 1 mm or less. Of these 84 patients, 49 were treated with surgery alone and 35 received immediate postoperative irradiation to doses of 50-70 Gy. The two patient groups are comparable with respect to stage of disease, age, male/female and racial ratios. This retrospective analysis, based on follow-up of 24-110 months, gives actuarial locoregional tumor control and survival data. The local control and disease-free survival rates in the combined modality group are significantly superior at the p = 0.0006 and p = 0.0003 levels, respectively, relative to the group treated with surgery alone. Patients in the combined modality group also experienced a significantly improved adjusted and overall survival, p = 0.005 and p = 0.01, respectively. The administration of postoperative irradiation was not associated with an increased rate of complications. The benefit of radiotherapy on survival was only seen when given as postoperative treatment but was lost in patients treated for salvage after tumor recurrence.

Effects of anti-TNF monoclonal antibody infusion in patients with hairy cell leukaemia

Tumour necrosis factor (TNF) can act as an autocrine growth factor for hairy cell leukaemia (HCL) cells. The TNF produced by the malignant clone may also inhibit normal haematopoiesis thereby contributing to the cytopenias observed in patients with the disease. We have studied the effects of infusing a murine monoclonal anti-TNF antibody in three patients with HCL. In two patients receiving 0.5 mg of antibody/kg on alternate days for 12 d, the drug was well tolerated. The third patient received 2 mg/kg on alternate days and developed symptoms of serum sickness by day 9. In two patients with severe B-lymphocytopenia, circulating CD19 and CD20 positive, B-cells were restored to normal, the majority of which were negative for the HCL-associated marker CD11c. B-lymphocyte recovery was associated with a rise in serum immunoreactive IL-6 and with an early rise in immunoreactive TNF. These short courses of anti-TNF MAb treatment had modest effect on the tumour burden, producing a reduction in splenomegaly in one patient. Exploration of the effects of more prolonged administration of higher dose anti-TNF antibody will only be feasible when less immunogenic MAbs are available.

[Uniform design for the best conditions of processing heixi in shenrong heixi pills] off

Uniform design has been applied to select the optimum technological conditions for processing Heixi in Shenrong Heixi Pills, using the contents of the main constituent of Heixi SNS as the optimum target. The best technological conditions have thus been found.

Self-focusing-induced saturable loss for laser mode locking

Self-focusing has recently been used for fast saturable absorber mode locking and femtosecond pulse generation in Ti:Al(2)O(3) lasers. We describe the operation, design, and optimization of self-focusing loss modulators for mode locking. A new formalism is developed that simplifies the treatment of self-focusing in thick nonlinear media by using a simple transform of the complex Gaussian beam parameter. Theoretical predictions are confirmed by experimental measurements.

Cardiac rehabilitation participation predicts lower rehospitalization costs

The effect of participation in cardiac rehabilitation on medical costs was determined by measuring hospitalization charges for cardiac admissions over a 3-year period in 580 post-coronary event patients (58% after coronary bypass surgery, 42% after myocardial infarction), of whom 230 entered a cardiac rehabilitation program and 350 did not. Baseline left ventricular ejection fraction was similar in entrants and nonentrants (59.9% vs 59.5%). Over the 1 to 46-month follow-up period (mean 21 months), per capita hospitalization charges for participants in cardiac rehabilitation were $739 lower than charges for nonparticipants ($1197 +/- 3911 vs $1936 +/- 5459, p = 0.022). This was due to both a lower incidence of hospitalizations and lower charges per hospitalization. Inasmuch as groups differed with regard to age, sex, diagnostic category, and smoking status, data were adjusted for these baseline differences by means of analysis of covariance. Rehospitalization charges remained significantly higher in nonparticipants (p = 0.015). Because physician charges were not measured, the cost differential between groups is underestimated. Results of this study show an association between participation in comprehensive cardiac rehabilitation and lowered cardiac rehospitalization costs in the years after an acute coronary event.